The present invention relates to thin peripheral devices for connection to conventional connectors where the connector requires dimensions greater than those of the device itself.
USB connectors are defined under standards available from the USB Implementers Forum, Inc. Different connector types have been specified over the years: A, B, mini A, mini B, mini AB. Each type was devised for a specific market; A for the PC platform, B for peripheral devices and the mini type for hand held devices. As a result, USB peripherals for the PC market have always been configured to mate with the “USB A” receptacle form.
FIG. 8 shows a drawing of standard USB A-type plug taken from the aforementioned standard and illustrating the external dimensions of the plug in millimeters. The insertable portion of the plug is about 12 millimeters long, about 11 millimeters wide and about 4 millimeters high, defined by a rectangular metal casing of shielding. An inner insulating block carrying four contact strips is about 2 millimeters thick.
In order to mate with the standard USB A receptacle, existing peripheral devices typically use one of two options. A first option is to use a cable to connect between the device and the PC receptacle. The use of cables/adaptors, while seeming to solve many form factor problems, has gained a very low customer acceptance, since the need to carry an additional item (cable or plastic adaptor) in addition to the peripheral device itself is an unwelcome additional burden on the customer.
The alternative to a cable is an “embedded connector” where the connector is formed as part of the device itself. While this option is relatively straight forward for many peripheral devices, it is particularly problematic for thin peripheral devices, specifically where one of the dimensions of the device is designed to be smaller than all the dimensions of a conventional USB A plug, i.e., less than about 4 millimeters.
Thus, conventional approaches to designing thin USB-compatible peripheral devices have taken one of two approaches:                1. According to one approach, a device as thin as 3.9-4.5 mm is formed with a connector or captive cable of conventional USB A plug dimensions, meaning the device is as narrow as the height of a standard USB connector A-type plug. An example of such a device is commercially available under the name “USBCard Pro™” from Freecom Technologies, Inc. (Berkeley, Calif.).        2. A second approach provides a device as thin as low as 2 mm with an embedded connector, while removing the metal casing around the plug. In this case, the inner connector structure remains the same as a conventional USB A-type plug without the metal casing. Such a device is disclosed in U.S. Pat. No. 6,883,718. An example of such a device is commercially available under the name “Intelligent Stick” or “I-Stick” from PQI Corp. (Fremont, Calif.). If the thickness of the embedded connector is reduced below 2 mm, it would no longer wedge reliably into the recess of the socket and the electrical connections would become unreliable.        
As a variant of this second approach, US Patent Application Publication No. 2004/0259423 A1 discloses selective application of resin to thicken specific regions, for example lateral ridges, of a thin dongle to the required 2 mm in order to provide reliable mechanical engagement with a standard USB socket.
Current card technology is capable of producing a wide range of devices of thickness less than 2 mm. Such devices are desirable for a range of applications including, but not limited to:                memory cards for hand held devices, similar to the Secure Digital (SD) card, that are required to be as thin as possible;        data storage devices that can be carried in a wallet;        data storage devices or authentication and payment devices that need to comply with ISO standards, for example functioning as credit cards or the like.        
The possibility of connecting such devices to a PC without the mediation of any external plug or connector would simplify many existing applications and facilitate many new applications or enhancements. It would therefore be advantageous to provide a memory storage device or other PCB-containing device with a thickness dimension less than 2 mm but which would maintain the capability of mating with a connector requiring dimensions of at least 2 mm, such as a standard USB A-type socket, thereby facilitating use of the device with a wide range of standard PC platforms.